Oral-care implements, such as manual toothbrushes and refills for power/electrical toothbrushes, comprising a plurality of cleaning filaments, or bristles, are well known in the art. Typically, the filaments are arranged in tufts and are attached to a mounting surface of a portion of the oral-care implement's plastic body (also known as a “head”) intended for insertion into a user's mouth. Typically, the tuft has an outer lateral surface having, overall, either a substantially cylindrical shape or a substantially rectangular shape. The filaments' free ends can be end-rounded or otherwise treated to eliminate sharp edges at the filaments' tips and hence their potential harmful effect on gums during brushing.
The oral-care implement's working surface, comprising a “surface” formed by the combined field of the filaments' tips, can be profiled to comprise any suitable shape, including, e.g. and without limitation, concave, convex, wavy, and the like shapes. A grip handle may be either removably attached to the head or made integral with the head. The former configuration is typical for a power brush, while the latter is for a manual brush.
Conventional cylindrical filaments have been used in a variety of oral-care implements. While some toothbrushes comprising cylindrical filaments can adequately clean the outer buccal face of teeth, they may have certain limitations with respect to providing effective removal of plaque and debris from the gingival margins, interproximal areas, lingual surfaces, and other hard-to-reach areas of the mouth. Smooth cylindrical surfaces and/or smooth tips of the conventional filaments are not effective for picking up and utilizing the particles in dentifrice. Nor can they have effective abrasion efficiency against dental plaque.
Therefore, toothbrush manufactures, in addition to conventional cylindrical filaments, have begun using filaments having a variety of shapes, including cross-sectional shapes, and a variety of surfaces, including textured surfaces. Non-cylindrical filaments and/or filaments having textured or roughened surface may provide a better plaque-removal and/or stain-removal efficacy. Non-limiting examples of non-cylindrical filaments include filaments having spiral or helical shapes, filaments having elliptical cross-sectional shapes, filaments having rectangular cross-sectional shapes, filaments having triangular cross-sectional shapes, filaments comprising X-shaped or cross-shaped cross-sections, filaments comprising star-shaped cross-section, filaments comprising bi-lobal and multi-lobal cross-sections, and the like. Oral-care implements having composite filaments, i.e., filaments comprising more than one material, are also known in the art.
Multiple attempts to design more effective filaments have been made. For example, U.S. Pat. No. 6,138,314 is directed to a toothbrush having an improved cleaning and abrasion efficiency. The bristles in that toothbrush contain longitudinal channels having a depth sufficient to entrap a quantity of abrasive particles such that during brushing with toothpaste, contact between the channel-entrapped abrasive particles and the surfaces of the teeth is improved. U.S. Pat. No. 3,613,143 is directed to a toothbrushes having abrasive impregnated bristles of two cross-section designs, i.e., to generally circular and polygon with the latter described as having longitudinal groove arrangements. U.S. Pat. No. 4,167,794 is directed to rounded bristles having shovel-like distal ends for more effective plaque removal. U.S. Pat. No. 4,958,402 is directed to fiber-flocking synthetic bristles that can retain and more effectively distributing a substance on the surface to be treated. U.S. Pat. No. 3,032,230 is directed to bristles having a polygon cross-section having at least two acute angles that impart a “scraping” effect on the teeth. U.S. Pat. No. 3,214,777 is directed to bristles having a rectangular cross-sectional area.
A variety of shapes of filaments and/or filament surfaces used in today's advanced oral-care implements creates a need to easily communicate, to a consumer, specific information pertaining to a particular type or types of filaments used in a given oral-care implement—and thus advantages provided thereby. A typical toothbrush can have from about 400 to about 1000 cleaning filaments. For example, in a basic brush having 36 tuft holes and an average number of filaments 24, there are 864 filaments altogether, tightly packed in tufts. If the filaments are stapled, i.e., bent in half, the number of their free ends is 1728. A typical cleaning filament's equivalent diameter, or an average cross-sectional dimension, is from about 0.1 mm to about 0.21 mm. Such a small size of an individual filament makes it virtually impossible for a naked human eye to see, much less assess, the individual filament's geometry, including the shape of the individual filament's tip or cross-section.
A commonly assigned application CM04051FQ, EP14158836.8, which is incorporated herein by reference, is directed to providing an oral-care implement's head comprising a plurality of filaments arranged in a tuft having a scaled-up shape with respect to the shape of the cross-sectional area of the individual filament.
In addition, information pertaining to functional characteristics of the filaments, including their geometry and cross-sectional shapes, can be communicated by using color forming certain shapes on the working surface of the oral-care implement. Likewise, information regarding the superior efficacy of the oral-care product, having those filaments, can be communicated to the consumer. The present disclosure is directed to accomplishing these tasks.